Speed limit is as annoying as the backseat driver in interrupting the driver's decision.
It is as if all drivers are wild and needed to be tamed.
But most people are not risk-takers and will drive at the speed that they are comfortable with.
Madmen will drive recklessly anyway without obeying the 101 traffic rules intended for them.

Humans are vulnerable so the crash at 80 kmph is as fatal as 300 kmph anyway.
The limit does not make any difference.

If all cars drive at speed limit, cars will be near to each other, increasing the chance of collision.
If there is a dangerous situation that needs speeding, drivers will be fined for keeping themselves alive.
Applying brake just to keep the speed limit is dangerous because that may cause rear-end collision.
Many times, dangerous acts, such as tailgating, sudden change of lane and hogging of overtaking lane are unpunished when the focus in on speed limit.
There will be drivers who do not follow the speed limit despite of the hefty fine so they may crash on the drivers who drive slower than them.

Germany implements no speed limit in some parts of their highway with success.
If the limit is removed, the government will save cost because each law needs money to enforce, such as installing limit signs.
Cars have top speed way beyond the speed limit, so if the government really wants to be our nanny, why does it not cap the speed of cars?
Or why does it not just allow horses on the road?